Voice amplification for primary school teachers with voice disorders: a randomized clinical trial

Several studies have demonstrated a high prevalence of voice disorders in teachers, together with the personal, professional and economical consequences of the problem. Good primary prevention should be based on 3 aspects: 1) amelioration of classroom acoustics, 2) voice care programs for future professional voice users, including teachers and 3) classroom or portable amplification systems. The aim of the study was to assess the benefit obtained from the use of portable amplification systems by female primary school teachers in their occupational setting.

Forty female primary school teachers attended a course about professional voice care, which comprised two theoretical lectures, each 60 min long. Thereafter, they were randomized into 2 groups: the teachers of the first group were asked to use a portable vocal amplifier for 3 months, till the end of school-year. The other 20 teachers were part of the control group, matched for age and years of employment. All subjects had a grade 1 of dysphonia with no significant organic lesion of the vocal folds.

Most teachers of the experimental group used the amplifier consistently for the whole duration of the experiment and found it very useful in reducing the symptoms of vocal fatigue. In fact, after 3 months, Voice Handicap Index (VHI) scores in "course + amplifier" group demonstrated a significant amelioration (p = 0.003). The perceptual grade of dysphonia also improved significantly (p = 0.0005). The same parameters changed favourably also in the "course only" group, but the results were not statistically significant (p = 0.4 for VHI and p = 0.03 for perceptual grade).

In teachers, and particularly in those with a constitutional weak voice and/or those who are prone to vocal fold pathology, vocal amplifiers may be an effective and low-cost intervention to decrease potentially damaging vocal loads and may represent a necessary form of prevention.